US1743108A - Furnace-arch structure - Google Patents

Description

1 Jan. 14, 1930. J. F. BOORAEM FURNACE Aficn STRUCTURE Filed Fep. 20, 1926 5 Sheets-Sheet l Jan. 14, 1930;

J. F. BOORAEM FURNACE ARCH STRUCTURE Filed Feb. 20, 1926 5 Sheets-Sheet 2 Jan. 14, 1930. J. F. BOORAEM FURNACE ARCH S TRUCTURE 5 Shets-Sheet :s

' Filed Feb. 20. 1926 Jan. 14, 1930. J. F. BOORAEM FURNACE ARCH STRUCTURE 1926 5 Sheets-Shee 4 Filed Feb. 20

Jan. 14, 1930. J. F. BOORAEM 1,743,108

FURNACE ARCH STRUCTURE Filed Feb. 20, 1926 5 Sheets-Sheet 5 Patented Jan. 14, 1930 PAT re ics JOHN FRANCIS BOORAEM, OF GBEENWICH, CONNECTICUT FURNACE-ARCH STRUCTURE Application med February 20, 1926. Serial No. 89,537.

This invention relates to furnace arch structures, and more particularlyto an arch structure of that type Which is built up of a multiplicity of assembled units or blocks of refractory material.

The present invention ismore particularly concerned with that more or less recent clevelopment in 'thisart in which atmospheric air is supplied to the under side of the arch through suitable passages formed in the arch block.

The object of the invention is to effect economies in the operation of furnaces by the introduction of fresh oxygen into the unconsu'med fuel gases While they are still subject to ignition and thus to obtain perfect and complete combustion and the full benefit of the fuel consumed.

, A further object of my invention is to control the velocity at Which the incoming air is discharged into the combustion chamber,rela-.

tive to any predetermined initial velocity or volume per minute at the points of ingress; and to introduce such control at the under side of the arch Wall to the end that a more perfect admixture of the air With the incompletely burned fuel gases may be obtained, thus insuring more perfect and complete combustion of the fuel With corresponding increased economy in the operation of the furnace.

Another object of the invention is to secure perfect mixture of the air With the unconsumed fuel gases so as to obtain complete combustion.

A feature of the present invention is the large areas of the air passages at their discharge ends, whereby the velocity of the incoming air is reduced to a minimum.

A further feature of the invention is the disposition of the discharge ends of certain of the air passages in planes perpendicular to the planes of other of the 'air passages Where- 5 by a thorough intermixing of the air with the unconsumed fuel gases is secured.

Another feature resulting from my improvements'resides in the cooling effect upon the refractory material Which prevents burning out of the exposed face of the block especially at its central portion and thus prolonging-the life thereof.

In a practical embodment of my present improvements, in addition to vertical air channels or passages in the opposite ends of the arch block which have their egress ends extending longitudinally of the arch wall, I provide air inlet passages .in "one or both of the side faces-of the block, the egress ends of which extend transversely of the Wall, and if desired, I may also provide additional air inlet passages through the body of the block extending inwardly and downwardly through its central portion and communicating with each other and h'avinga c mmon outlet opening on the exposed face of the block. In certain instances Where higher velocity of the air is desirable these latter passages may be omitted. However, in many cases Where a greater volume is required, the larger number of openings or passages in the blocks permit the passage of such large volume of air with less friction for any given rate of flow of the air through the intake port of the harness from Which the arch structure is suspended. By means of my improvements it is also possible, in the erection of an arch Wall for a particular furnace to employ various combinations ofthe arch blocks having relatively different arrangements of the air passages. It is, therefore, evident that the utility of such arch blocks or units insatisfactorily meeting peculiar conditions incident to the structural and economic design of the furnace may be appreciably enhanced. At the same time, "however, the use of my improvements does not increase the cost of production of the arch blocks over that incident to the manufacture of such arch blocks as heretofore employed in the art.

lVith the above and other objects inview,

the invention consists in the improved furnace arch structure and in the form, construction and relative arrangement of its several parts as Will be hereinafter more fully described, illustrated in the accompanying drawings, and subsequently incorporated in the subjoined claims.

I In the drawings, wherein I have disclosed several simple and practical embodiments of my present improvements and in which similar reference characters designate corresponding parts throughout the several views;--

Figure 1 is a side elevation partly in sec tion showing a furnace arch block provided with one embodiment of the present invention;

Fig. 2 is an end elevation thereof, a portion of the block being sectioned substantially on the line 22 of Fig. 1;

Fig. 3 is a bottom plan view; I

Fig. 4 is a side elevation of an arch block showing another form of my improvements;

Fig. 5 is a bottom plan view thereof;

Fig. 6 is a side elevation partly in section illustrating another-embodiment of the invention;

Fig. 7 is an end elevation partly in section of the arch block shown in Fig.6;

Fig. 8 is a top plan view;

Fig. 9 is an end elevation of said block;

Fig. 10 is a side elevation partly in section of an arch block showing another alternative embodiment of the invention;

Fig. 11 is an end elevation thereof;

Fig. 12 is a bottom plan view of said block;

Fig. 13 is a view similar to Fig. 10 showing a slightly different form of such construction;

Fig. 14 is a perspective view showing an arch block in which the arrangement of air inlet passages shown in Figs. 1 and 10 of the drawings are combined: 7

Fig. 15 is transverse section of a portion of the arch showing the block suspended from the air supply tubes of the harness;

Fig. 16 is a perspective view similar to Fig. 14 showing another alternative form of the arch block;

Figs. 17, 18, 19 and 20 are detail views partly in section of arch blocks embodying features shown in the preceding Views but omitting the vertical air passages in the end faces of the block;

Fig. 21 is aside elevation of a block partly in section showing still another alternative form thereof;

Fig. 22 is a detail view showing two of the blocks illustrated in Fig. 9 as they appear in acent rows of the arch wall structure;

Figs. 23 and 24 are detail fragmentary views showing slightly different forms of the arch blocks whereby they may be arranged in an undulating or curvilinear wall structure;

Fig. 25 is a vertical sectional view through an arch block of my new construction taken substantially on the line aa of Fig. 14;

Fig. 26 is a transverse section, the block being shown partly in elevation, said section being taken substantially on the line b-b of Fig.14;

of the removable wedge members for locking the blocks of the arch to the harnessv ele ments; V

Fig. 29 is a fragmentary perspective view showing an arrangement of my improved blocks in one of the side walls of the furnace combustion chamber, and

Fig. 30 is a detailsection showing another arrangement of the blocks at one end of the combustion chamber.

In each of the illustrated examples of my present improvements, I have shownthe refractory arch block or brick in the form of a cube of proper predetermined proportions whereby such block may beconveniently applied to and suspended from a harness structure traversing the furnace chamber at the upper side thereof. Therefore, each arch block generally indicated at 1 is provided with a reduced portion whereby recesses 2 are formed at opposite sides thereof to receive elements of the harness structure. This reduced portion of the block has its opposite faces at the inner sides of the recesses 2 obliquely inclined as shown at 3. For convenience in description, I shall refer to the surfaces of the individual 'arch' block which extends transversely of the'furnace structure when the blocks are assembled in the arch wall, as the side faces thereof and to those surfaces of the arch block which extend longitudinally of the furnace structure as the end faces thereof. These end faces of the arch block are provided with vertically extending recesses or channels 5, the upper ends of which communicate with the tube receiving recesses 2, said channels gradually flaring or increasing in width to their other egress ends as indicated at 6. Preferably, the bottom face of the block which is exposed to the combustion chamber of the furnace is inwardly and downwardly inclined or tapered as shown at 6 from the opposite ends of the brick to an intermediate horizontal surface 8 thereof, and these tapering surfaces 6 are provided with channels or recesses 7 communicating with the lower ends of the channels 6 and gradually decreasing in depth and finally merging into the surface 8.

air receiving tubes 15 by suitable couplings 14. The tubes 15 are suitably mounted or supported at their ends in the walls of the furnace structure and air is drawn into and through these tubes by induction created by the draft through the furnace chamber. This atmospheric air passing through the couplings 14 into the tubes 4 is drawn through I suitable openings at. in the walls of the latter tubes and downwardly into the furnace chamber in a manner which willfbe'hereinafter M more fully described.

The individual arch blocks are detachably locked to the tubes 4 by the removable wedge members 18 which are inserted bet-ween the opposite sides of the tubes and the walls of the recesses 2 in the arch blocks in adjacent rows. Preferably, the tubes 4 are in the form of sh rt sections arranged end to end longitudinally of the furnace in abutting engagement with each-other, said tube sections each being connected with one of the header tubes 15 by one of the couplings 14. It'will be noted from reference to Fig. 15 of the drawings, that the wedge members 18 shown in detail in Fig. 28, when placed in position between the inclined faces 3 of the blocks and the adjacent tube sections 4 terminate at their lower ends above the faces of therecesses 2 in the blocks, thus providing a space 4* between the lower side of each tube section l and the arch blocks into which the air is initially del vered through the openings 4: in said tube sections and from which it is drawn into the upper or ing ess ends of the several air receiving passages in the arch blocks to be hereinafter referred to.

WVhile the arch block provided with the air passages 5 results in an increase in efliciency and economical operation of the furnace by providing an additional supply .of oxygen at the under side of the arch wall, it has been found in certain large installatlons for inclustrial purposes that, owing to the expansion of s the mcommg air, there is great frictional resistance due to increase in pressure which re sults in opposition to the draft through the furnace chamber. Accordingly, the volume of air drawn into the combustion chamber at the egress ends of the passages is appreciably less than the initial volume of airwhich enters the header tubes of the harness structure. This small volume of air is drawn at great velocity by the draft to the outlet flue before such air has completely given up the minor percentage of oxygen contained therein so that all of the oxygen will not mix the fuel gases and be ignited before the air is drawn into the outlet flue of the furnace. The velocity of t 1e incoming air at the ingress end of the passages 5 is of course, determined by the relative areas of the tubes 4 and the out let stack of the furnace. In order to decrease the velocity with which the incoming air is drawn through the furnace' chamber to the outlet flue, it is therefore, necessary to increase the area of the passages admitting the air through the arch'structure to the furnace chamber, and in proportion to such increase in volume, the velocity at the inner side of the arch wall will be reduced so that the oxygen contained in the air may 'becompletely utilized in the promotion of perfect combustion cating with each other at their lower ends and opening upon the lower face 8 oftheblock to provide a relatively narrow egress end 10 extending substantially across the entire width of said face 8. The lower side of each of the tubes 4 of the harness structure has suitable openings 11. therein registering with the upper ingress ends of the diverging branches 9 of'said air passages, and is also provided with additional openings 12 to register with the mating passages 5 in the con tacting end faces of the arch block in adjacent rows.

However, it is possible as shown in Figs.4 and 5 of the drawings, to supply the air to the passages in both the end and side faces ofthe block through a common opening in the harness tube. Thus, the body of the block may be formed with a transverse opening 13 therethrough communicating at its opposite ends with the upper ends of the air passages 9 in the side faces of the block. inwardly and downwardly inclined openings 16 communicate at their inner ends centrally with the opening 1.3 and at their outer ends open upon the faces of the recesses 2 of the block in line with the upper ends of the vertical passages 5 in the end faces of the block. In this case, it will be apparent that the lower side of the harness tube may be provided with a circumferentially elongated opening or slot therein extending over the ends of the openings 16 and the passages 5.

In Figs. 6 to 9 inclusive, I have shown a slightly different form of the block illustrated in Fig. 1, wherein the upper ends ofthe diverging branches 9 of the air passages in opposite side faces of the block are connected with each other by cutting away the faces of the recesses 2 as shown at 17. Preferably though not necessarily, the base walls of the passages 9 are connected and merged with other at their upper ends by a curved or con vex surface so that no obstruction or impediment will be offered to the free distribution of the air in substantially equal volume to the channels or passages in the opposite side faces of the block.

' In Figs. 10 to 12, I have disclosed another alternative block construction for the purpose of supplementing the air supply to the furnace chamber wherein the block is not pro vided with the air passages or channels in its opposite side faces-but in lieu thereof downwardly and inwardly inclined passages 19 are formed through the body of the block,

said passages opening at their upper ends upon the faces of the recesses 2 and communicating with each other at their lower ends to form a common elongated egress opening 20 on the bottom or exposed face of the block substantially at the center thereof; In Fig. 18 I have illustrated an alternative of this arrangement of the passages wherein said In Fig. 14 of the drawings, I have shown a number of the blocks as assembled in the arch wall and having combined in the structure thereof, the end and side air passages as in Fig. 1, together with the additional air passages 19 of Fig. 10 extending through the body of the block and opening upon its lower face between the egress ends 10 of the passages in the side faces thereof. Such a construction of the arch block supplies air in maximum volume to the under side of the arch wall, and even though the incoming air is heated and expanded, owing to the large combined area of the several passages, frictional resistance to the flow of the air is reduced so that there will be no back pressure through the passages and the volume of air entering the furnace chamber per minute will therefore, be proportional to the total passage area and the initial volume entering the harness tubes. By providing these tubes .with suitable dampers, the volume of air drawn into the combustion chamber of the furnace may be accurately controlled. Thus,

of, the block.

ample opportunity is afforded for the oxygen contained in the incoming air to mix with the unconsumed fuel gases'and insure combustion thereof before the air is finally drawn into the outlet fine.

In Fig. 16 of the drawings, I have shown a block construction in which each block is V provided with a single longitudinally and transversely extending obliquely inclined air passage'22 through the body thereof in addition to the vertical passages 5 in-the end faces This passage 22 at its upper end opens upon the face of one of the recesses 2 at the center thereofas shown at 23 and at its lower end opens upon one side face of the block as at 24, this latter opening extending substantially the entire width of the bottom surface 8 of the block and having its upper edge suitably spaced above said bottom face. This construction, as well as those shown 11]. Figs. 1 and 6, provides a trans versely elongated'egress opening for the air at the adjacent faces of the blocks in each row so that in addition to supplying air to the under side of the arch in the required volume,

the refractory material is kept relatively cool" so that the central portion of the block will not rapidly burn away.

In Fig. 17 of the drawings, I have shown an arch block provided with the air inlet passages 9 in the opposite side faces thereof and the vertically inclined passages 19 extending through the body of the block, but omitting the vertical passages 5 in the end faces of the block. In Fig. 18, I have shown a block provided only with the passages 9' in its side faces while in Fig. 19 I have shown a block having the connected passages in its side faces as in Fig. 6 and provided with the inclined passages 19 through the body there- 7 of as in Fig. 10 but omitting the end passages 5. In Fig. 20, I have illustrated a block of the same construction as in Fig. 4, but omitting the end passages 5. r

In Fig. 21 of the drawings, I have shown a slightly different construction of the arch block in which ingress openings 25 are downwardly inclined from the faces of the recesses 2 and communicate at their inner ends with connected upwardly inclined passages 26 having their egress ends 27 opening upon opposite side faces of the block and said egress ends of the passages at the lower sides thereof I communicating with the downwardly inclined channels 7 on the lower faceof the block at its opposite ends.

In Fig. 22 of the drawings, I have illustrated blocks of the type shown in Fig. 6 Without the passages 5 in the end faces thereof as they would be assembled in the arch wall while Figs. 23 and 24 show different types of blocks having their end faces disposed in nonparallel relation to each other so that the rows of blocks may be arranged in an arch Wall structure of curved form and with the end faces of the blocks in adjacent rows in closely contacting relation. As indicated in Fig. 16 of the drawings, each block may be provided in its reduced upper end portion.

with suitable means whereby-the block may be conveniently handled and assembled in the wall structure or removed therefrom.

In addition to the use of myimproved refractory blocks in the furnace arch wall construction, they may in many instances also be advantageously used in the sidewalls or in the upwardly sloping rear end wall of the combustion chamber. Thus, in Fig. 29 of the drawings, I have shown a row of the blocks of the type illustrated in Fig. 1 arranged in the side wall 25 of the combustion'chamber, said wall having a horizontall extending channel providedtherein for t e reception of the blocks 1. The reduced end portions of the blocks abutting against the inner side wall of thischannel provide the spaced air passages. 26 which communicate.- with the-;external atmosphere. The diverging branches ofthe passages 91 in the individualblocks re: spectively, communicate with the, main air supply passagesv 26 while the passages 5in the upper and lower end faces of the block likewiserespectively communicate with the pas-. sages 26 and have their egress, ends located above and below the egress ends of the pas sages 9 and intermediate of the latter. In Fig.30 of the drawings, I haveshown a similar arrangement of the blocks in the rear upwardly sloping wall 27 of the combustion chamber. It will of course, be understood that any desired number of rows of the blocks.

may be arranged in the walls 26. and 27.

From the foregoing description considered in connection with the accompanying drawings, the construction and several advantages of the different alternative forms of the arch block embodying my present improvements will be clearly understood. It will be seen that by such constructions I accomplish two important results. First, by selecting the proper combinations of the different types of blocks, I may so regulate the volume of the air admitted to the furnace chamber through the arch wall, as to obtain any desired predetermined velocity and volume per minute thereof, and thus utilize all of the oxygen contained in the air and secure complete combustion of the fuel gases, and secondly, by the admission of the larger volume of air and particularly at the contacting side faces of the arch blocks in the same row, the heat is more effectively absorbed and radiated from the block structure so that the latter is kept at a relatively low temperature, thus preventing burning away of the exposed face of the arch block especially at the central portion thereof.

Passage of air from atmospheric pressure and boiler room temperature (89 F.) admitting one volume at the inlet meets a condition at the point of egress in a furnace where at that point the temperature is 2000 F. such that the unit volume will become five volumes and consequently, unless unrestricted, or unless allowed freedom to expand to five times the volume would develop five times the pressure, if held at same volume. This pressure, if not reduced by increase in volume, would if restricted proportionately increase pressure on the sidewalls of the ducts automatically retard the flow at the point of egress and correspondingly reduce the capacity of the inlet end of the harness to let in a sufficient amount of free air to meet the possible maximum required at a point of egress for the temperature condition existing and the demands of the conditions for the supply of oxygen. By having five times the volume and no greater pressure agalnst the Walls of the duct by virtue of having five times the capacity, there is removed the tendency of retardation due to friction which Would be induced by the pressure a d a direct result of this, there is. removed any res tardation to the inflow of air into; the harness unit, and thus its delivery capacity is not decreased against the will of the open. ator.

In the event of the inletopening of the harness giving too much air under these conditions the amountrequired in cubic feet perminute can be'controlled by a damper. The; result obtained is, a rarefied and open molecu lar condition air at less density than atmospheric which combines easier with the carbon oxide because of the open condition of the. moleculars.

With five times the volume at 2000 F. from 89 F. in the blocks to handle, the volume is increased five timesby the configuration of the passages, and there is removed the ten: dency of this air to move at five times the speed andtherefore it ispossibleto control the speed. The more ducts, the less speed, and by a modification of the configuration of thepassages in the blocks the control of the speed can be also accomplished. I have shown inthe drawings the cross-sectional area increas. ing by change of; one lateral dimension only, but it is possible to also change or widenthe other lateral dimension, and thus increase the volume much more rapidly for a given unit of length. Thus, the speed can be controlled to, meet a given set of general combustion chamber conditions, There istherefore, pro. vided a combustion chamber having blocks with passages, the air at the inlet ends Off which is at atmospheric, or forced draft;pres-. sure andat boiler room temperature and the air at the outlet ends of which is distributed on the combustion surface of theblocks, the.

passages; increasing in volume from theirxine let ends to their outletends in proportion to the increase of temperature of the blocks from the inlet to the outlet ends so that the I have herein disclosed several practical v constructions whereby the desiredresults may sorting to all such legitimate changes in the.

constructionand relative arrangement of. the

several features of myinventioa as may be fairly embodied Within the spirit and scope of the appended claims.

I'claim: i 1.. In afurnace arch construction, a plural- .ity of rows of refractory blocks, the contactrection at right angles to the egress end of the first mentioned passage, and means for supplying air to the other ends of said passa es. J

5. In a furnace arch construction, a plurality of rows of refractory blocks, individual blocks in each roW being of cube form and having air inlet passages in opposite faces thereof opening at their egress ends upon the exposed face of the block, and said block in another face thereof having an additional air inlet passage also opening at its egress end upon the exposed face of the block, said egress end extending in a direction at right angles to the egress end of said first mentioned passage, and means for supplying air to the other ends of said passages.

3. A refractory block for furnaces substantially of cube form having air passages in its structure one of Which is provided with diverging branches having ingress ends for communication with spaced air supply means, and theegress end of said passage being elongated and opening upon the face of the block Which forms the exposed surface of the combustion chamber Wall of the furnace, the other passage having an egress end opening on the exposed surface of the block in a plane per pendicular to the first mentioned egress end.

4. A refractory block for furnaces substantially of cube form having air inlet passages in its opposite side faces, each of said passages having diverging branches providing spaced ingress ends to said passages adapted for communication With spaced'air supply means, and the egress end of each of said 7 passages opening upon theface of the block Which forms the exposed surface of the combustion chamber Wall of the furnace, in parallel planes, and the block having additional air passages having egress ends opening upon the exposed face of the block in planes perpendicular to the planes of the first mentioned egress ends. w p

5. In a furnace wall const uction, a'row of refractory blocks having contacting and adjoining faces provided With mating air inlet passages, each passage including diverging branches opening at their ingress ends into non-communicating air supply passages in of also communicating at their ingress ends- With the respective air supply passages in the Wall structure and opening at their egress ends into the combustion chamber of the furnace between the egress ends of the first named air inlet passages, and in planes perpendicular to the planes of the first named passages.

In testimony that I claim the foregoing as my invention, I have signed my name hereto.

JOHN FRANCIS BOORAEM.

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